1. Field of the Invention
The present invention relates generally to non-combustible construction materials and, more particularly, to a non-combustible blanket material for preventing the spread of fire. Specifically, the present invention relates to a non-combustible heat expandable material in the form of a fire block ranging in consistency from pliable to rigid to be used in various industrial, commercial, transportation and construction applications.
2. Description of the Prior Art
The use of prestressed, precast concrete panels, including curtain wall, in the construction of buildings is well known in the construction arts. Such panels may be used to clad the exterior walls of buildings and may also serve as portions of interior walls. In forming walls from such panels, the panels are purposely spaced apart a predetermined amount to allow for expansion and contraction. The width of the gap or joint between these wall panels is generally on the order of one-fourth inch to one inch.
It has been found that when one surface of a wall formed from such panels is exposed to fire, the capacity of the wall to withstand heat and to prevent the spread of fire to the area on the opposite side of the wall is largely dependant upon the type of material used to fill or seal off the joints between panels.
A problem encountered in joint preparation for resisting the penetration of heat and/or flames has been that during fire conditions an air pressure differential develops between the side of the wall exposed to the fire and the opposite side of the wall. The heat of the fire tends to shrink or burn away and subsequently destroy any sealant material provided at the surface of a joint and the pressure differential between the two sides of the wall tends to cause any other material which is positioned within the joint to be blown out of position or to be distorted or destroyed, allowing the rapid passage of air and thus heat and/or flame from the fire side of the wall to the opposite side of the wall. Once such a flame passage through the joint is provided, fire and smoke spread quickly through the wall to the adjoining area, thus defeating the otherwise excellent fire resistant properties of prestressed, precast concrete and curtain wall panels.
Moreover, in a wide variety of manufactured articles as well as in applications other than joint construction sealing, it would be highly desirable to provide a fire proof mechanism in the form of an effective fire proof covering. For example, the interior walls of airplanes, automobiles and the like are generally very thin and structurally weak. In an event of a fire, the heat and flames can spread very rapidly through the interior walls and into the vehicle compartment. A blanket of fire proof material designed into the wall panel of such vehicles would help inhibit, at least temporarily, the spread of flames and fire thereby providing additional time for passenger evacuation. In other construction applications, such as building walls and ceilings, a wide variety of different sized openings are provided for electrical utilities, plumbing and the like. Fire may readily spread through such openings in the manner described above for wall joints unless an appropriate fire retaining blanket or sheet system is applied thereto.
In order to prevent the spread of fire through joints and other wall or ceiling openings, various joint treatments have been utilized in the past which provide a layer of blanket-like fire resistant material which is supported in position by a polyethylene, closed-cell backup strip positioned adjacent to the fire proof blanket material or alternately positioned near the opposite wall surface of the joint in an attempt to stabilize the fire resistant blanket material within the joint. A problem with such prior art solutions has been that the handling and installation of this blanket material and foam rod combinations is usually relatively slow and labor intensive and thus considerably increases the cost of joint preparation making them very expensive.
Various materials and procedures for forming fire resistant joints are discussed in a publication of the Portland Cement Association entitled "Fire Tests of Joints Between Pre-Cast Concrete Wall Panels: Effects of Various Joint Treatments" by A. H. Gustarerro and M. S. Abrams, PCI Journal, September/October 1975, pages 44-64. This report indicates that it is known to treat a joint for fire prevention by placing a neoprene tube filled with ceramic fibers in a portion of the joint slightly recessed from one wall surface and to thereafter seal off the recess space between the neoprene tube and wall face with a joint sealing material such as polyoxide urethane sealant. A problem with the use of a neoprene tube filled with ceramic fibers is that neoprene has limited heat resistance and produces substantial smoke emission when it oxidizes. Another problem is that the placement of ceramic fiber into a tube is extremely slow and expensive and is therefore impractical in lengths of more than a few inches.
The prior art limitations described above relative to prevention of fire propagation through joints are also applicable to the prevention of the spread of fire through other wall and ceiling openings as well as to the delay of fire propagation in the construction of vehicles such as automobiles, airplanes and the like. Thus, there is a need for effective, yet simple, fire proof manufacture and construction materials and systems.